Improvement of breakdown characteristics of a GaAs power field-effect transistor using (NH4)2Sx treatment

A (NH4)2Sx solution treatment technique was applied to a GaAs metal-semiconductor field-effect transistor (MESFET) to improve the electrical properties of the transistor. The gate leakage current of the MESFET remarkably decreased while the drain breakdown voltage doubled to 30 V with the (NH4)2Sx treatment. The (NH4)2Sx treatment was found to effectively suppress the formation of donor-type defects at the GaAs surface and to increase the Schottky barrier height.